4 + 5- custom trays + final impressions

why do you block out undercuts when making custom trays

triad shrinks as it sets, therefore the custom tray would be locked/stocked after curing is the undercuts are not blocked out

2 types of techniques when making custom trays

1. wash: triad directly applied to tissues

2. spaced: baseplate wax applied to tissues before triad

which custom tray technique is better

spaced b/c there’s less pressure on the tissue → less likely to distort hyperplastic/non-attached tissues + create pain on non-resilient tissues

when is spaced technique less necessary

on primary stress bearing areas

ex: thicker mucosa, cortical bone. attached gingiva

where on the maxilla is spacing less necessary 

1. primary bearing area: horizontal portion of hard palate 

2. secondary bearing area: residual ridge 

where on the mandible is spacing less necessary 

1. primary bearing areas: buccal shelf + retromolar pad

2. secondary bearing areas: crest of residual ridge 

where on the maxilla is spacing more necessary 

1. rugae area

2. medial palatal suture 

3. incisive papilla 

4. sharp spiny processes 

5. torus 

advantage of spaced technique

all undercuts will be automatically blocked out

what makes triad shrink when it cured

due to polymerization of a network of urethane dimethylmethacrylate + absence of methylmethacrylate

what component of triad makes it light curable

Camphoroquinone that reacts to light in a range of 400-500 nm

why do you need to put these balls here before putting on the triad

balls create vertical stops to maintain a uniform amount of space between the typodont + trays

how long do you cure the triad 

7 min total 

what is the 1st step of the 2nd appt

custom trays are placed in pt’s mouth + assessed for support, stability, retention

when should the custom tray be adjusted

if there are any over-extensions, to relieve any frenum, and sharp edges that cause pain to pt

5 objectives of an impression

1. provide retention

2. provide stability

3. provide support

4. provide esthetics for the lips 

5. maintain health of oral tissues 

R S S E H 

definition of support

resistance to vertical components of mastication + occlusal forces applied in the direction of the basal seat

definition of retention

resistance to removal in a direction opposite that of its insertion

definition of stability 

quality of a denture to be firm, steady, and constant in position when horizontal forces are applied to it

2 primary areas of support

1. maxilla: horizontal segment of the palate

2. mandible: buccal shelf + posterior ridges

secondary areas of support

crest of the ridge of max + mand

3 components of retention 

1. adhesion: physical attraction of unlike particles 

2. cohesion: physical attraction of like materials 

3. peripheral seal + atmospheric pressure

adhesion depends on what

close adaptation of the denture + size of the bearing area

cohesion depends on what

1. interfacial surface tension: resistance to separation to a fill of liquid

2. mechanical locking into undercuts: must be handled carefully as to not creat sore spots + abraded tissue

what’s the only way to capture a peripheral seal

border molding

6 factors that are required for stability

1. good retention

2. non-interfering occlusion: if occlusion is off, stability will be off (Bilateral Balanced Occlusion)

3. proper tooth arrangement: best if teeth are placed on the ridge

4. proper form an contour of the polished surfaces

5. proper orientation of the occlusal plane.

6. good control + coordination of the patient’s musculature

what material is used for border molding in clinic 

compound sticks 

what material is used for border molding in preclin

VPS (vinylpolysiloxane)

what are compound sticks made of

• 40% natural resins (thermoplastic properties)

• 7% waxes (thermoplastic properties)

• 3% stearic acid (lubricant + plasticizer)

• 50% fillers + pigments

what are the 3 types of compound sticks + their working temps

1. soft green: 122-124 F

2. gray: 128-130 F

3. red: 130-132 F

what’s the sequence of maxillary structures in border molding

1. labial vestibule 

2. buccal vestibule (one side then the other)

3. posterior palatal seal 

what’s the sequence of mandibular structures in border molding

1. sublingual crescent area

2. mylohyoid area (one side then the other)

3. retromylohyoid area (one side then the other)

4. buccal vestibule (one side then the other)

5. labial vestibule 

how to get functional border molding of the max +mand labial vestibule

ask pt to overtly move the lips by saying “Ouh! Ah! E!”

how to do manual manipulation of muscles for border molding of the max labial vestibule

1. pt cannot understand instructions: mental impairment or language barrier

2. muscular disability: Parkinson’s disease or tardive dyskinesia

how to get functional border molding of the max + mand buccal vestibule

ask pt to do fish face

how to do manual manipulation of muscles for border molding of the buccinator of max + mand buccal vestibule

cheek is: 

1. elevated 

2. pulled downward, outward, inward, forward for orbicularis oris action, backward for buccinator action 

how to get functional border molding of the coronoid process of max buccal vestibule

ask pt to move mandible side to side 

how to get functional border molding of the pterygo-mandibular raphe of PPS

ask pt to open as wide as possible

how to locate the 3 landmarks of the posterior palatal seal (PPS)

1. anterior outline: press gently against hard palate w/ ball burnisher + work backward until displaceable tissue is located

2. depth: press burnisher against soft tissue to approximate amount of displacement

3. posterior outline (vibrating line): based on movement of soft palate muscles + fovae palatinae

how to get functional border molding of vibrating line of PPS

ask pt to say long “ah” or do valsava maneuver

how to get functional border molding of the masseter of the mand buccal vestibule

hold down custom tray + instructing pt to close

how to get functional border molding of sublingual crescent area of the alveololingual sulcus

1. anterior lingual flange length: ask pt to protrude the tongue out as it activates the genioglossus muscle, which raises sublingual fold

2. anterior lingual flange thickness: push tongue against front part of the palate

how to get functional border molding of mylohyoid area of the alveololingual sulcus

ask pt to move tongue to opposite cheek + push tongue against front part of palate

how to get functional border molding of retromylohyoid area of the alveololingual sulcus

1. ask pt to open wide ppterygomandibular raphe to be brought forward

2. thrust tongue out so superior constrictor of pharynx pushes mylohyoid muscle

3. ask pt to close → downward pressure on mandible activate medial pterygoids push against retromylohyoid curtains distal end of lingual flange

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summarize all the movements the pt must do to capture border molding of the alveololingual sulcus

1. tongue out

2. tongue to front part of palate

3. tongue to R + L cheeks

4. open wide

5. close